Urban development on any natural drainage basin causes marked changes in the runoff characteristics of the basin. Urbanization alters natural drainage channels and reduces average infiltration rates. Thus, flood conditions are enhanced both within the urbanizing area itself and at downstream locations, where existing channels might not be able to cope with the increased rates of water flow. The Olympus Cove area in Salt Lake County is undergoing rapid urban development, and potential flood hazards within the area and at downstream locations are thereby increasing. Recognizing this situation, officials of the Sale Lake County took the initiative in organizing an ‘ad hoc’ interagency technical team to study and evaluate the problem. The particular responsibilities which were undertaken by the representatives of the Utah Water Research Laboratory on this study team were to synthesize all existing information, and what which might be developed during the study period, and on this basis to formulate computer models to represent the hydrology of the area. The report describes the model development process and discusses the application of the models to the three source areas being considered, namely: (1) the Neff’s Canyon drainage; (2) the northern slopes of Mt. Olympus; and (3) the urbanizing area of Olympus Cove. Runoff from the short-term, high-intensity, convective storms is emphasized. Hydrologic response was found to be particularl